Here is some more specific confirmation I just found on escortfocus.com
Although the basic design of the 2.0L engines has remained the same since ’97, Ford has made several changes to the block and heads over the last seven years, so it takes at least three short blocks, two heads and four completes to cover everything through 2003, including all the applications for both the Escort and Focus.
BLOCKS
There have been three blocks used since ’97.
1997 – The original 2.0L block was a F7CE-AA/AB casting that can be identified by the PCV vent hole on the driver’s side that has three bolt holes in a triangular pattern surrounding it.
1998-’99 – There was one small, but important change made to the block in ’98. Ford added a machined pad for a knock sensor on the passenger side, right between the second and third cylinders, just below the deck surface. It would be pretty hard to add this boss to a ’97 block, so plan on using this later version for the ’98 and ’99 applications. Look for a F8CE-AA casting.
2000-’01 – The block was revised one more time in 2000. The YS4E-DA casting looked just like the earlier F8CE-AA block with the hole for the knock sensor on the right side and the pad for the PCV on the left side, but the vent hole wasn’t machined and the three small holes around it weren’t drilled because the PCV system was changed so they were no longer needed.
2002-’03 – We’re not aware of any specific changes to the block in 2002, but the Ford catalog shows a different part number for the short block, so there may or may not be a difference in the block.
HEADS
There have been two heads used on these motors, one for the Escort and another for the Focus:
1997-’02 Escort – The original split-port head (c/n F7CE-AA) that came out in ’97 was used for the Escort until it was finally discontinued in 2002. It has a "Dee" shaped chamber, beehive springs, two intake ports leading to each intake valve, and eight 8.0mm bolt holes that are used to attach the intake manifold.
2001-’03 –When the 2.0L engine was installed in the Focus, it came with a unique cylinder head. It still had the split ports, but there were seven 6.0mm bolt holes arranged in a slightly different pattern for the intake manifold. This head also had four big bolt holes in the front for the torque-axis motor mount that was used on the Focus. It’s a YS4E-DA casting. It will bolt on to the other blocks but the intake manifolds are not interchangeable. The axis motor mount (top mount on the passenger side) will not interchange due to the difference in the bolt patterns. It may be possible to make it work.
FRONT COVER
The Escort came with a plastic cover behind the timing belt, but the Focus didn’t have one. The one that was used on the Escort is available as a part number F7CZ-6019-AA.
